Abaixo está uma instrução que descreve uma tarefa de geração de SQL, combinada com uma entrada que fornece mais contexto sobre os esquemas de tabela disponíveis. Escreva o código SQL que responda adequadamente à solicitação
 ###Instrução: Que oponente tem um jogo com menos de 6, e 17 de abril como data?
 ###Tabelas: CREATE TABLE bafa_national_leagues (bafa_national_leagues_id AUTO_INCREMENT PRIMARY KEY, Team VARCHAR, Location VARCHAR, Years in senior / adult league VARCHAR, 2013 BAFA Adult division VARCHAR, 2013 BAFA Adult flag division VARCHAR, 2013 BAFA Junior division VARCHAR, Other teams VARCHAR) CREATE TABLE playoffs (playoffs_id AUTO_INCREMENT PRIMARY KEY, Game INT, Date VARCHAR, Opponent VARCHAR, Score VARCHAR, Series VARCHAR) CREATE TABLE doubles_36_20–16 (doubles_36_20–16_id AUTO_INCREMENT PRIMARY KEY, Outcome VARCHAR, Date VARCHAR, Tournament VARCHAR, Surface VARCHAR, Partner VARCHAR, Opponents in the final VARCHAR, Score in the final VARCHAR) CREATE TABLE keyboard_"feel"_feature_matrix_for_current_models (keyboard_"feel"_feature_matrix_for_current_models_id AUTO_INCREMENT PRIMARY KEY, Model VARCHAR, Graded Hammer (Non GH3) VARCHAR, Graded Hammer Three (GH3) VARCHAR, Natural Wood Keyboard VARCHAR, Synthetic Ivory Keytops VARCHAR) CREATE TABLE most-visited_countries_by_international_tourist_arrivals (most-visited_countries_by_international_tourist_arrivals_id AUTO_INCREMENT PRIMARY KEY, Rank INT, Country VARCHAR, UNWTO Region VARCHAR, International tourist arrivals (2012) VARCHAR, International tourist arrivals (2011) VARCHAR, Change (2011 to 2012) VARCHAR, Change (2010 to 2011) VARCHAR)  
SELECT Opponent FROM playoffs WHERE Game < 6 AND Date = april 17